Workers in the United States spend large amounts of time on the job, making the workplace a key venue for preventive health programs. A workplace risk that has received limited attention is solar ultraviolet radiation (UVR). Unprotected exposure to solar UVR of outdoor workers can produce both an immediate acute harm (i.e., severe sunburn) and long-term skin damage that can elevate the risk of developing skin cancers. Preventing skin cancer is a priority due to its high prevalence; tendency to recur; association with other cancers; and lost productivity ($66.9 billion in losses were attributed to melanoma-related mortality from 1990-2008). Sun Safe Workplaces (SSW) is a comprehensive occupational sun safety education and policy intervention that was tested by our research team in a randomized control trial with 98 cities, counties, and special districts in Colorado. Post testing will be completed in November 2013. The SSW intervention focused on three sectors in the organizations: public works, public safety, and parks and recreation. Half of the employers received the SSW intervention, with the remaining employers in the control condition receiving basic sun safety information. Our preliminary analyses indicate that 80% of employers in the SSW intervention condition provided sun safety education to employees and 36% adopted formal sun protection policies. No control organizations reported policy adoption. In this application, we propose to conduct a 2-year follow-up study on the benefits of the SSW intervention (i.e., increasing employees' sun protection) and return on investment (ROI; benefits relative to intervention costs). Employee behavior was not assessed in the current SSW trial because it was uncertain whether the SSW intervention would result in uptake of education and policy and thus have the potential to influence their sun protection practices. The proposed 2-year follow-up of the 98 organizations in the SSW trial will include: (1) surveys with employees (n=10,787) and front line supervisors (n=767) to assess employees' sun protection practices and workplace actions to support employee sun safety; (2) on-site observations of sun protection actions by the employers (e.g., posters, sunscreen, shade structures); and (3) tracking of the costs of implementing the SSW intervention and induced employer costs. The proposed analyses will compare the sun protection practices of employees a) between workplaces that received the SSW intervention and controls and b) among workplaces that provided education and adopted policy, provided education only, and control workplaces. Analyses will determine if the extent of sun protection actions by employers influences employees' sun safety practices. The economic evaluation will estimate the ROI (i.e., comparison of the estimated program benefits to combined cost elements). The proposed study is significant and innovative because it provides critical information applicable to a wide range o industrial sectors with outdoor workers on a workplace risk that has received scant attention. Determining the effectiveness and ROI of prevention programs is essential for national and local resource investment.